Culture

The cultivation of cells in the laboratory. Bacteria and yeasts may be grown suspended in a liquid medium or as colonies on a solid medium; molds grow on moist surfaces; and animal and plant cells (tissue cultures) usually adhere to the glass or plastic beneath a liquid medium. Cultures must provide sources of energy and raw material for biosynthesis, as well as a suitable physical environment.

The materials supplied determine which organisms can grow out from a mixed inoculum. Some bacteria (prototrophic) can produce all their constituents from a single organic carbon source; hence they can grow on a simple medium. Other cells (auxotrophic) lack various biosynthetic pathways and hence require various amino acids, nucleic acid bases, and vitamins. Obligatory or facultative anaerobes grow in the absence of O2; many cells require elevated CO2. Cultures isolated from nature are usually mixed; pure cultures are best obtained by subculturing single colonies. Viruses are often grown in cultures of a host cell, and may be isolated as plaques in a continuous lawn of those cells. In diagnostic bacteriology, species are ordinarily identified by their ability to grow on various selective media and by the characteristic appearance of their colonies on test media. See also Bacterial growth.

Laboratory cultures are often made in small flasks, test tubes, or covered flat dishes (petri dishes). Industrial cultures for antibiotics or other microbial products are usually in fermentors of 10,000 gallons (37,850 liters) or more. The cells may be separated from the culture fluid by centrifugation or filtration.

Specific procedures are employed for isolation, cultivation, and manipulation of microorganisms, including viruses and rickettsia, and for propagation of plant and animal cells and tissues. A relatively minute number of cells, the inoculum, is introduced into a sterilized nutrient environment, the medium. The culture medium in a suitable vessel is protected by cotton plugs or loose-fitting covers with overlapping edges so as to allow diffusion of air, yet prevent access of contaminating organisms from the air or from unsterilized surfaces. The transfer, or inoculation, usually is done with the end of a flamed, then cooled, platinum wire. Sterile swabs may also be used and, in the case of liquid inoculum, sterile pipets.

The aqueous solution of nutrients may be left as a liquid medium or may be solidified by incorporation of a nutritionally inert substance, most commonly agar or silica gel. Special gas requirements may be provided in culture vessels closed to the atmosphere, as for anaerobic organisms. Inoculated vessels are held at a desired constant temperature in an incubator or water bath. Liquid culture media may be mechanically agitated during incubation. Maximal growth, which is visible as a turbidity or as masses of cells, is usually attained within a few days, although some organisms may require weeks to reach this stage. See also Chemostat; Embryonated egg culture; Tissue culture.

Fine Art

Fine art refers to arts that are "concerned and designates a limited number of visual art forms, including painting, sculpture, architecture and printmaking. Schools, institutes, and other organizations still use the term to indicate a traditional perspective on the visual arts, often implying an association with classic or academic art.

The word "fine" does not so much denote the quality of the artwork in question, but the purity of the discipline. This definition tends to exclude visual art forms that could be considered craftwork or applied art, such as textiles. The more recent term visual arts is widely considered to be a more inclusive and descriptive phrase for today's variety of current art practices, and for the multitude of mediums in which high art is now more widely recognized to occur. Ultimately, the term fine in 'fine art' comes from the concept of Final Cause, or purpose, or end, in the philosophy of Aristotle. The Final Cause of fine art is the art object itself; it is not a means to another end except perhaps to please those who behold it.

An alternative, if flippant, reference to "fine art," is capital "A" art, or, art with a capital "A."

The term is still often used outside of the arts to denote when someone has perfected an activity to a very high level of skill. For example, one might metaphorically say that "Pelé took football to the level of a fine art."

That fine art is seen as being distinct from applied arts is largely the result of an issue raised in Britain by the conflict between the followers of the Arts and Crafts Movement, including William Morris, and the early modernists, including Virginia Woolf and the Bloomsbury Group. The former sought to bring socialist principles to bear on the arts by including the more commonplace crafts of the masses within the realm of the arts, while the modernists sought to keep artistic endeavour exclusive, esoteric, and elitist.

Confusion often occurs when people mistakenly refer to the Fine Arts but mean the Performing Arts (Music, Dance, Drama, etc). However, there is some disagreement here, as, for example, at York University, Fine Arts is a faculty that includes the "traditional" fine arts, design, and the "Performing Arts".

An academic course of study in fine art may include a Master of Fine Arts degree.

Types of fine art

* Drawing
* Film
* Fine art photography
* Intermedia (interdisciplinary, traditionally referred to as Fine Art Media)
* Literature

* Painting
* Printmaking
* Sculpture
* Textiles

Earth

Earth

Earth is the third planet from the Sun and is the largest of the terrestrial planets, in terms of both diameter and mass. Earth is also referred to as "the Earth", "Planet Earth", "Gaia", "Terra", or "the World".

The Earth is the first planet known to have liquid water on the surface and is the only place in the universe known to harbor life. Earth has a magnetic field that, together with a primarily nitrogen-oxygen atmosphere, protects the surface from radiation that is harmful to life. The atmosphere also serves as a shield that causes smaller meteors to burn up before they strike the surface.

The Earth formed around 4.57 billion years[1] ago and its only known natural satellite, the Moon, began orbiting it around 4.53 billion years ago. At present the Earth orbits the Sun once for every roughly 366.26 times it rotates about its axis (which is equal to 365.26 solar days), a period known as the sidereal year. The Earth's axis of rotation is tilted 23.4° relative to the Sun, producing seasonal variations on the planet's surface.

Atmospheric conditions on Earth have been significantly altered by the presence of life forms, which create an ecological balance that modifies the surface conditions. About 71% of the surface is covered in salt-water oceans, and the remainder consists of continents and islands. The outer surface is divided into several tectonic plates that gradually migrate across the surface over geologic time spans. The interior of the planet remains active, with a thick layer of convecting yet solid mantle, a liquid outer core that generates a magnetic field, and a solid-iron inner core.

The space environment interacts with the Earth to a significant degree. The relatively large moon provides ocean tides, stabilizes the axial tilt and has gradually modified the length of the planet's rotation period. A cometary bombardment during the early history of the planet played a role in the formation of the oceans. Later, asteroid impacts caused significant changes to the surface environment. Long term periodic changes in the orbit of the planet are believed to have caused the ice ages that have covered significant portions of the surface in glacial sheets.


History

Current scientists have been able to reconstruct detailed information about the planet's past. Earth formed 4.57 billion years ago[1] out of the solar nebula, along with the Sun and the other planets. Initially molten, the outer layer of the planet cooled to form a solid crust when water began accumulating in the atmosphere. The Moon formed soon afterwards, possibly as the result of a Mars-sized object with about 10% of the Earth's mass,[2] known as Theia, impacting the Earth in a glancing blow.[3] Some of this object's mass merged with the Earth and a portion was ejected into space, but enough material survived to form an orbiting moon.

Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, augmented by ice delivered by comets, produced the oceans.[4] The highly energetic chemistry is believed to have produced a self-replicating molecule around 4 billion years ago, and half a billion years later, the last common ancestor of all life existed.[5]

The development of photosynthesis allowed the sun's energy to be harvested directly by life forms; the resultant oxygen accumulated in the atmosphere and gave rise to the ozone layer. The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes.[6] True multicellular organisms formed as cells within colonies became increasingly specialized. Aided by the absorption of harmful ultraviolet radiation by the ozone layer, life colonized the surface of Earth.[7]

Over hundreds of millions of years, continents formed and broke up as the surface of Earth continually reshaped itself. The continents have migrated across the surface of the Earth, occasionally combining to form a supercontinent. Roughly 750 million years ago (mya), the earliest known supercontinent Rodinia, began to break apart. The continents later recombined to form Pannotia, 600–540 mya, then finally Pangaea, which broke apart 180 mya.[8]

Since the 1960s, it has been hypothesized that severe glacial action between 750 and 580 mya, during the Neoproterozoic, covered much of the planet in a sheet of ice. This hypothesis has been termed "Snowball Earth", and is of particular interest because it preceded the Cambrian explosion, when multicellular life forms began to proliferate.[9]

Following the Cambrian explosion, about 535 mya, there have been five mass extinctions.[10] The last extinction event occurred 65 mya, when a meteorite collision probably triggered the extinction of the (non-avian) dinosaurs and other large reptiles, but spared small animals such as mammals, which then resembled shrews. Over the past 65 mya, mammalian life has diversified, and several mya, an African ape-like animal gained the ability to stand upright.[11] This enabled tool use and encouraged communication that provided the nutrition and stimulation needed for a larger brain. The development of agriculture, and then civilization, allowed humans to influence the Earth in a short time span as no other life form had, affecting both the nature and quantity of other life forms.

The present pattern of ice ages began about 40 mya, then intensified during the Pleistocene about 3 mya. The polar regions have since undergone repeated cycles of glaciation and thaw, repeating every 40–100,000 years. The last ice age ended 10,000 years ago.


Composition and structure

Earth is a terrestrial planet, meaning that it is a rocky body, rather than a gas giant such as Jupiter. It is the largest of the four solar terrestrial planets, both in terms of size and total mass. Of these four planets, Earth also has the highest density, the highest surface gravity and the strongest magnetic field.


Shape

The Earth's shape is very close to an oblate spheroid—a rounded shape with a bulge around the equator—although the precise shape (the geoid) varies from this by up to 100 metres (327 ft).[14] The average diameter of the reference spheroid is about 12,742 km (7,913 mi). More approximately the distance is 40,000 km/π because the metre was originally defined as 1/10,000,000 of the distance from the equator to the north pole through Paris, France.

The rotation of the Earth creates the equatorial bulge so that the equatorial diameter is 43 km (27 mi) larger than the pole to pole diameter. The largest local deviations in the rocky surface of the Earth are Mount Everest (8,848 m [29,028 ft] above local sea level) and the Mariana Trench (10,911 m [35,798 ft] below local sea level). Hence compared to a perfect ellipsoid, the Earth has a tolerance of about one part in about 584, or 0.17%, which is less than the 0.22% tolerance allowed in billiard balls.[15] Because of the bulge, the feature farthest from the center of the Earth is actually Mount Chimborazo in Ecuador.

Chemical composition

The mass of the Earth is approximately 5.98 ×1024 kg. It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminum (1.4%); with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is believed to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements.[17]

The geochemist F. W. Clarke calculated that a little more than 47% of the earth's crust consists of oxygen. The more common rock constituents of the Earth's crust are nearly all oxides; chlorine, sulfur and fluorine are the only important exceptions to this and their total amount in any rock is usually much less than 1%. The principal oxides are silica, alumina, iron oxides, lime, magnesia, potash and soda. The silica functions principally as an acid, forming silicates, and all the commonest minerals of igneous rocks are of this nature. From a computation based on 1,672 analyses of all kinds of rocks, Clarke deduced that 99.22% were composed of 11 oxides (see the table at right.) All the other constituents occur only in very small quantities.

Internal structure

The interior of the Earth, like that of the other terrestrial planets, is chemically divided into layers. The Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core. The crust is separated from the mantle by the Mohorovičić discontinuity, and the thickness of the crust varies: averaging 6 km under the oceans and 30–50 km on the continents.[19]

The geologic component layers of the Earth[20] are at the following depths below the surface:[21]
Depth Layer Density
g/cm3
Kilometres Miles
0–60 0–37 Lithosphere (locally varies between 5 and 200 km) —
0–35 0–22 ... Crust (locally varies between 5 and 70 km) 2.2–2.9
35–60 22–37 ... Uppermost part of mantle 3.4–4.4
35–2890 22–1790 Mantle 3.4–5.6
100–700 62–435 ... Asthenosphere —
2890–5100 1790–3160 Outer core 9.9–12.2
5100–6378 3160–3954 Inner core 12.8–13.1

The internal heat of the planet is most likely produced by the radioactive decay of potassium-40, uranium-238 and thorium-232 isotopes. All three have half-life decay periods of more than a billion years.[22] At the center of the planet, the temperature may be up to 7,000 K and the pressure could reach 360 GPa.[23] A portion of the core's thermal energy is transported toward the crust by Mantle plumes; a form of convection consisting of upwellings of higher-temperature rock. These plumes can produce hotspots and flood basalts.


Surface

The Earth's terrain varies greatly from place to place. About 70.8%[29] of the surface is covered by water, with much of the continental shelf below sea level. The submerged surface has mountainous features, including a globe-spanning mid-ocean ridge system, as well as oceanic trenches, submarine canyons, oceanic plateaus and abyssal plains. The remaining 29.2% not covered by water consists of mountains, deserts, plains, plateaus, and other geomorphologies.

The planetary surface undergoes reshaping over geological time periods due to the effects of tectonics and erosion. The surface features built up or deformed through plate tectonics are subject to steady weathering from precipitation, thermal cycles, and chemical effects. Glaciation, coastal erosion, the build-up of coral reefs, and large meteorite impacts[30] also act to reshape the landscape.

As the continental plates migrate across the planet, the ocean floor is subducted under the leading edges. At the same time, upwellings of mantle material create a divergent boundary along mid-ocean ridges. The combination of these processes continually recycles the ocean plate material. Most of the ocean floor is less than 100 million years in age. The oldest ocean plate is located in the western Pacific, and has an estimated age of about 200 million years. By comparison, the oldest fossils found on land have an age of about 3 billion years.[31][32]

The continental plates consist of lower density material such as the igneous rocks granite and andesite. Less common is basalt, a denser volcanic rock that is the primary constituent of the ocean floors.[33] Sedimentary rock is formed from the accumulation of sediment that becomes compacted together. Nearly 75% of the continental surfaces are covered by sedimentary rocks, although they form only about 5% of the crust.[34] The third form of rock material found on Earth is metamorphic rock, which is created from the transformation of pre-existing rock types through high pressures, high temperatures, or both. The most abundant silicate minerals on the Earth's surface include quartz, the feldspars, amphibole, mica, pyroxene and olivine.[35] Common carbonate minerals include calcite (found in limestone) and dolomite.

The pedosphere is the outermost layer of the Earth that is composed of soil and subject to soil formation processes. It exists at the interface of the lithosphere, atmosphere, hydrosphere and biosphere. Currently the total arable land is 13.31% of the land surface, with only 4.71% supporting permanent crops.[36] Close to 40% of the Earth's land surface is presently used for cropland and pasture, or an estimated 3.3 × 109 acres of cropland and 8.4 × 109 acres of pastureland.[37]
Elevation histogram of the surface of the Earth—approximately 71% of the Earth's surface is covered with water.
Elevation histogram of the surface of the Earth—approximately 71% of the Earth's surface is covered with water.

The elevation of the land surface of the Earth varies from the low point of −418 m (−1,371 ft) at the Dead Sea, to a 2005-estimated maximum altitude of 8,848 m (29,028 ft) at the top of Mount Everest. The mean height of land above sea level is 686 m (426 ft).


Hydrosphere

The abundance of water on Earth surface is a unique feature that distinguishes the "Blue Planet" from others in the solar system. The Earth's hydrosphere consists chiefly of the oceans, but technically includes all water surfaces in the world, including inland seas, lakes, rivers, and underground waters down to a depth of 2,000 m. The deepest underwater location is Challenger Deep of the Mariana Trench in the Pacific Ocean with a depth of −10,911 m (35,798 ft or 6.78 mi).[39] The average depth of the oceans is 3,794 m (12,447 ft), more than five times the average height of the continents.[38]

The mass of the oceans is approximately 1.35 × 1018 tonnes, or about 1/4400 of the total mass of the Earth, and occupies a volume of 1.386 × 109 km³. If all of the land on Earth were spread evenly, water would rise to an altitude of more than 2.7 km (approximately 1.7 mi).[40] About 97.5% of the water is saline, while the remaining 2.5% is fresh water. The majority of the fresh water, about 68.7%, is currently in the form of ice.[41]

About 3.5% of the total mass of the oceans consists of salt. Most of this salt was released from volcanic activity or extracted from cool, igneous rocks.[42] The oceans are also a reservoir of dissolved atmospheric gases, which are essential for the survival of many aquatic life forms.[43] Sea water has an important influence on the world's climate, with the oceans acting as a large heat reservoir.[44] Shifts in the oceanic temperature distribution can cause significant weather shifts, such as the El Niño-Southern Oscillation.

Atmosphere

The atmospheric pressure on the surface of the Earth averages 101.325 kPa, with a scale height of about 6 km. It is 78% nitrogen and 21% oxygen, with trace amounts of water vapor, carbon dioxide and other gaseous molecules. The atmosphere protects the Earth's life forms by absorbing ultraviolet solar radiation, moderating temperature, transporting water vapor, and providing useful gases.[45]

In a phenomenon known as the greenhouse effect, trace molecules within the atmosphere serve to capture thermal energy emitted from the ground, thereby raising the net temperature. Carbon dioxide, water vapor, methane and ozone are the primary greenhouse gases in the Earth's atmosphere. Without this heat-retention effect, the average surface temperature would be -18°C and life would likely not exist.


Weather and climate

The Earth's atmosphere has no definite boundary, slowly becoming thinner and fading into outer space. Three-quarters of the atmosphere's mass is contained within the first 11 km (about 4 mi) of the planet's surface. This lowest layer is called the troposphere. Energy from the Sun heats this layer, and the surface below, causing expansion of the air. This lower density air then rises, and is replaced by cooler, higher density air. The result is atmospheric circulation that drives the weather and climate through redistribution of heat energy.[46]

The primary atmospheric circulation bands consist of the trade winds in the equatorial region below 30° latitude and the westerlies in the mid-latitudes between 30° and 60°.[47] However, ocean currents are also important factors in determining climate, particularly the thermohaline circulation that distributes heat energy from the equatorial oceans to the polar regions.

Water vapor generated through surface evaporation is transported by circulatory patterns in the atmosphere. When atmospheric conditions permit an uplift of warm, humid air, this water condenses and settles to the surface as precipitation.[46] Most of the water is then transported back to lower elevations by river systems, usually returning to the oceans or being deposited into lakes. This water cycle is a vital mechanism for supporting life on land, and is a primary factor in the erosion of surface features over geological periods. Precipitation patterns vary widely, ranging from several metres of water per year to less than a millimetre. Atmospheric circulation, topological features and temperature differences determine the average precipitation that falls in each region.[48]

The Earth can be sub-divided into specific latitudinal belts of approximately homogeneous climate. Ranging from the equator to the polar regions, these are the tropical (or equatorial), subtropical, temperate and polar climates.[49] Climate can also be classified based on the temperature and precipitation, with the climate regions characterized by fairly uniform air masses. The commonly-used Köppen climate classification system (as modified by Wladimir Köppen's student Rudolph Geiger) has five broad groups (humid tropics, arid, humid middle latitudes, continental and cold polar), which are further divided into more specific subtypes.

Psychology of education

Educational psychology is the study of how humans learn in educational settings, the effectiveness of educational interventions, the psychology of teaching, and the social psychology of schools as organizations. Although the terms "educational psychology" and "school psychology" are often used interchangeably, researchers and theorists are likely to be identified as educational psychologists, whereas practitioners in schools or school-related settings are identified as school psychologists. Educational psychology is concerned with the processes of educational attainment in the general population and in sub-populations such as gifted children and those with specific disabilities.

Educational psychology can in part be understood through its relationship with other disciplines. It is informed primarily by psychology, bearing a relationship to that discipline analogous to the relationship between medicine and biology. Educational psychology in turn informs a wide range of specialities within educational studies, including instructional design, educational technology, curriculum development, organizational learning, special education and classroom management. Educational psychology both draws from and contributes to cognitive science and the learning sciences. In universities, departments of educational psychology are usually housed within faculties of education, possibly accounting for the lack of representation of educational psychology content in introductory psychology textbooks (Lucas, Blazek, & Raley, 2006).

Education process

Learning modalities

There has been a great deal of work on learning styles over the last two decades. Dunn and Dunn[1] focused on identifying relevant stimuli that may influence learning and manipulating the school environment, at about the same time as Joseph Renzulli recommended varying teaching strategies. Howard Gardner identified individual talents or aptitudes in his Multiple Intelligences theories. Based on the works of Jung, the Myers-Briggs Type Indicator and Keirsey's Temperament Sorter focused on understanding how people's personality affects the way they interact personally, and how this affects the way individuals respond to each other within the learning environment. The work of David Kolb and Anthony Gregorc's Type Delineator follows a similar but more simplified approach.

Education can be divided into many different learning "modes" but the learning modalities are probably the most common:

Kinesthetic learning based on hands-on work and engaging in activities. Visual learning based on observation and seeing what is being learned. Auditory learning based on listening to instructions/information. Depending on their preferred learning modality, different teaching techniques have different levels of effectiveness. Effective teaching requires a variety of teaching methods which cover all three learning modalities. No matter what their preference, students should have equal opportunities to learn in a way that is effective for them.

Teaching

Primary School in "open air". Teacher (priest) with class from the outskirts of Bucharest, around 1842.Teachers need the ability to understand a subject well enough to convey its essence to a new generation of students. The goal is to establish a sound knowledge base on which students will be able to build as they are exposed to different life experiences. The passing of knowledge from generation to generation allows students to grow into useful members of society. Good teachers are able to translate information, good judgment, experience, and wisdom into a significant knowledge of a subject that is understood and retained by the student.

Methodist

The Methodist revival originated in England. It was started by a group of men including John Wesley and his younger brother Charles as a movement within the Church of England in the 18th century, focused on Bible study, and a methodical approach to scriptures and Christian living. The term "Methodist" was a pejorative college nickname that was given to a small society of students at Oxford, who met together between 1729 and 1735 for the purpose of mutual improvement. They were accustomed to communicate every week, to fast regularly and to abstain from most forms of amusement and luxury. They also frequently visited poor and sick persons and prisoners in the jail.